To be fair, he isn't even that bad looking right now even. That one popular picture of him right now with the Ao Oni comparison suffers from shitty lighting, but if you see his face anywhere else, he just looks like a normal 30 year old. He would probably look even better if he bothered to actually exercise, get good sleep, and stop living such a stressful life.
Of course, his life is stressful because he isn't programming Yandere Simulator, and he is going to continue being stressed as long as he keeps up the deception and doesn't finish his game, which at this point is indefinitely.